A 22-year-old woman with a history of type 1 diabetes mellitus is brought to the emergency… — USMLE Step 2 CK

A $22$ -year-old woman with a history of type $1$ diabetes mellitus is brought to the emergency department by her roommate due to severe lethargy, nausea, and diffuse abdominal pain for the past day. She has been unable to tolerate oral intake following a recent upper respiratory infection. Her temperature is $37.8^\circ\text{C}$ ( $100.0^\circ\text{F}$ ), blood pressure is $88/54\text{ mmHg}$ , pulse is $128/\text{min}$ , and respirations are $28/\text{min}$ with deep, sighing breaths. The patient appears clinically dehydrated with dry mucous membranes. Capillary blood glucose is $610\text{ mg/dL}$ . Initial laboratory studies are as follows:

Serum sodium: $132\text{ mEq/L}$
Serum potassium: $3.1\text{ mEq/L}$
Serum chloride: $98\text{ mEq/L}$
Serum bicarbonate: $10\text{ mEq/L}$

Arterial blood gas shows a pH of $7.12$ . Urinalysis is strongly positive for ketones.

Arrange the following management steps in the most appropriate chronological sequence for this patient.

1Initiate aggressive intravenous fluid resuscitation with $0.9\%$ normal saline
2Administer intravenous potassium chloride
3Initiate continuous intravenous regular insulin infusion
4Add $5\%$ dextrose to the intravenous fluids
5Transition to a subcutaneous basal-bolus insulin regimen

Cevap

The correct sequence of management is: intravenous fluid resuscitation, followed by potassium chloride repletion, then initiation of intravenous insulin, later addition of dextrose to IV fluids, and finally transitioning to subcutaneous insulin.

The optimal management of diabetic ketoacidosis involves a highly structured algorithmic approach. Step 1: Intravenous normal saline is the most urgent intervention to correct profound volume depletion and shock. Step 2: Because this patient has a serum potassium level < 3.3 mEq/L, insulin must be withheld and potassium chloride administered first. Step 3: Once potassium is safely ≥ 3.3 mEq/L, intravenous regular insulin is started to suppress ketogenesis and resolve the acidosis. Step 4: As insulin lowers the blood glucose, 5% dextrose must be added to the IV fluids once glucose drops to ~200 mg/dL to prevent hypoglycemia, as the insulin infusion must continue until the anion gap closes. Step 5: After the anion gap closes and the patient can eat, an overlap with subcutaneous insulin is performed before discontinuing the IV insulin.

Adım Adım Çözüm

Initiate intravenous fluid resuscitation with 0.9% normal saline.

Restores intravascular volume and improves renal perfusion.

The patient is hypotensive and severely dehydrated from osmotic diuresis; volume expansion is the most urgent initial step in diabetic ketoacidosis (DKA) management.

Administer intravenous potassium chloride.

Corrects the severe total body potassium deficit.

The initial serum potassium is critically low (< 3.3 mEq/L). Administering insulin first would drive potassium intracellularly, precipitating life-threatening arrhythmias.

Initiate continuous intravenous regular insulin infusion.

Halts lipolysis, ketogenesis, and gluconeogenesis.

Once potassium is confirmed to be ≥ 3.3 mEq/L, insulin is started to reverse the ketoacidosis and close the anion gap.

Add 5% dextrose to the intravenous fluids.

Prevents iatrogenic hypoglycemia while continuing insulin therapy.

When the serum glucose falls below 200-250 mg/dL, dextrose must be added because insulin is still required to fully clear the ketones and close the anion gap.

Transition to a subcutaneous basal-bolus insulin regimen.

Maintains glycemic control outside the acute setting.

Once the anion gap is closed, the patient is hemodynamically stable, and oral intake is tolerated, IV insulin can be overlapped and transitioned to subcutaneous insulin.

Anahtar Kavram

Stepwise management of Diabetic Ketoacidosis (DKA) with severe initial hypokalemia

Tahmini Süre:1m 30s

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